1. Field of the Invention
The present invention relates to a diagnostic apparatus for circulatory systems, particularly to a diagnostic apparatus for circulatory systems having an ultrasonic tomogram function using a probe inserted into a circulatory system, and an X-ray radiograph function.
2. Description of the Related Art
In recent years, there has been developed an ultrasonic catheter apparatus for obtaining an ultrasonic tomogram by using a catheter inserted into a blood vessel. An ultrasonic transducer is provided in a distal end of the catheter and an ultrasonic wave is radially scanned so that the 360.degree. ultrasonic tomogram of the blood vessel around the distal end of the catheter is obtained. Although this apparatus allows an operator to observe the whole cross-section of the wall of the blood vessel, it has a drawback that it is not possible to know the location of the ultrasonic tomogram in the blood vessel.
In order to know the location of the ultrasonic tomogram it is necessary to use an X-ray diagnostic apparatus together with the ultrasonic catheter apparatus. Prior to the insertion of the ultrasonic catheter, a catheter for injecting a contrast medium into the blood vessel is inserted into the blood vessel, and, by injecting the contrast medium, a roadmap image is obtained which indicates the shape of the blood vessel. Then, while the ultrasonic catheter is inserted and the ultrasonic tomogram of the blood vessel is being obtained, X-ray radiation is also performed which gives a live image of the blood vessel. This live image shows the shape of the catheter, and thereby it is possible to determine the exact position of the ultrasonic catheter by comparing the live image with the roadmap image.
However, even though the location of the distal end of the ultrasonic catheter can be determined, the orientation of the patient cannot be known from the ultrasonic tomogram. More particularly, when a stenosis of the blood vessel is found in the ultrasonic tomogram, it cannot be determined whether the stenosis is present on the heart side of the vessel or not.
Further, in order to install two apparatuses in an examination room it is necessary to have an extremely large space. In addition, simultaneous operation of the two apparatuses is quite cumbersome for handling.
These drawbacks are present not only when the ultrasonic catheter apparatus for diagnosis is used but also when an ultrasonic catheter apparatus for treatment, for example, a balloon catheter, is used.